Hedyotis diffusa (H. diffusa) Willd. is known to induce apoptosis in cancer cells. However, the molecular mechanism of its anti-cancer activity has not been fully elucidated. In this study, we found that the ethanol extract of H. diffusa Willd. (EEHDW) reduced cell viability and induced apoptosis in a dose- and time-dependent manner in human leukemic THP-1 cells. The induction of apoptosis was also accompanied by the down regulation of PI3K/Akt and the inhibitor of apoptosis protein (IAP) family proteins. Moreover, we observed that EEHDW treatment resulted in activation of caspase-3, which may partly explain the anti-cancer activity of EEHDW.Key words: Hedyotis diffusa Willd., THP-1, apoptosis, caspase
